Tuning fork anvil



; T\mme FORK 1mm.

Filed Jan. 23, 1962 J. SINGERMAN 3,180,198

Sheets-Shut l 1 April 27, 1965 Filed Jan. 23, 1962 J. SINGERMAN 3,180,198

TUNING FORK ANVIL 2 Sheets-Sheet 2 INVENTOR.

United States Patent 3,180,198 TUNING FORK ANVEL Joseph Singerman, New York, N.Y. (7020 108th St., Forest Hills, NY.) Filed Jan. 23, 1962, Ser. No. 168,171 6 Claims. (Cl. 84-453) This invention relates to an effective anvil, of special design, upon which to strike a tuning fork.

In a number of school laboratory experiments, for example, the teacher and the students find it necessary to activate a tuning fork. It had been, for years, standard practice for the experimenter to strike the fork on the heel of his shoe. This is, at best, an awkward procedure. There are, however, an increasing number of experimenters wearing feminine shoes of such design that this technique is ruled out. Striking the fork against the furniture, as is often being done, results not only in unwanted noise, but also in marring either or both the furniture and the fork.

' Another device tried in schools is the use of a squat form rubber stopper. As will be explained hereinafter, this is very unsatisfactory.

Another device in the prior art is a rubber headed mallet. This is unsatisfactory for two reasons. Since the fork is usually held by the stem with the fingers of one hand while being struck by the mallet in ones other hand, the energy imparted to the fork tines is found to be extremely limited. This is particularly so in the case of persons who, lacking mechanical agility, swing with a stiff wrist. In View of this disadvantage, some manufacturers offer a rubber mallet head each face of which is of a different degree of hardness, one for so-called low frequency forks, the other for high frequency forks.

The fact that manipulation of the mallet requires the use of both hands, simultaneously, is another disadvantage. My invention overcomes these disadvantages.

Another device in the prior art comprises a rubber bumper affixed to each of the tines of a tuning fork. This has two disadvantages. The rubber bumper would wear or be chipped thru use and, thereupon, suffer a change in the vibratory characteristics of its tines. Secondly, this does not provide for energizing standard forks manufactured without the special bumpers.

It is one object of this invention to make it possible to have one hand free to manipulate another element of the apparatus, such as a resonance tube, While energizing the tuning fork.

It is another object of this invention to make it easy for the experimenter to impart, at will, an appreciable amount of energy to the tuning fork tines.

Another object of this invention is to obviate the need for surfaces of different degrees of hardness for energizing forks of different frequency ranges.

A further object of this invention is to provide a construction which is economical to manufacture and assemble.

A still further object of this invention is to provide a device which, when struck with a tuning fork, will not bound, slide or bounce from its initial position on a table.

These and other vadvantages and objects are apparent from the following description in which reference is made to the accompanying drawings.

In the drawings:

FIGURE 1 is a perspective view of one form of the invention.

FIGURE 2 shows a vertical, longitudinal section thru the model shown in FIGURE 1.

impact surface, such as 55 in FIGURE 3, presents a more or less cylindrically convex area. The role played by the convexity of the area will hereinafter be explained. In use, the tuning fork to be energized is struck upon the impact surface, in the usual manner. The operator,

without any conscious effort, swings the fork thru a plane perpendicular to a longitudinal axis of the anvil. The tine of the fork will impinge upon the impact surface within several degrees of a vertical, as within the area delineated by 5-5, more or less, in FIGURE 3. This is so for two reasons. In the first place, the operator, standing at the laboratory table, will normally tend to strike the impact surface in approximately a vertical direction. Secondly, he is constrained not to deviate appreciably from a vertical because then the tine of the fork would strike the protruding edge of the base.

Because of the convexity of the impact surface, the anvil does not bound or creep forward in reaction to the impact. This happens, for example, when the squat rubber stopper, placed upon a table, is used as an anvil. The impact compresses the rubber. Upon its rapid recovery from this compression, the inertia of the mass of rubber causes it to bound forward, frequently bouncing off the near edge of the table, much to the consternation and exasperation of the experimenter. The onlyway to prevent this is to provide a heavy base or, what amounts to the same thing, clamp the anvil to the table top. The disadvantage is obviated by use of a body portion presenting a convex surface.

Apparently, the effectiveness of the convex Surface is due to a diffusion of the impact stress more or less in all directions having downward and horizontal components, in a plane perpendicular to a longitudinal axis of the anvil. Upon recovery from the resulting strains, in the rubber, the more or less equal tendency to bound in either horizontal direction cancel each other. Much of the compressional energy imparted to the rubber is dissipated internally. The resultant recovery in an upward direction is too feeble to cause the slab to rise, even with a base of very low mass.

Almost invariably, the experimenter will. strike the fork not far from the middle of the body portion, so that recovery of the rubber will not result in a tendency to bound in either longitudinal direction. If one were to strike the body portion near either end, then the anvil will tend to bound somewhat in that direction. But, it will not bound off the edge of the table. Therefore, and also in view of the fact that it is unlikely the experimenter will strike near either end, this is not a serious consideration. However, a surface of a spherical nature would obviate this possibility, as all the horizontal components will practically cancel each other out.

A more economical assembly is depicted in FIGURE 3. In the process of molding the base 6, it is caused to overlap the wide lower edges of the body portion 7, thereby forming an integral assembly without the need for additional operations. Labor required for assembly is reduced and no adhesive is required.

Another economical assembly is depicted in FIGURE 4. In theprocess of molding the base 8, it is designed so.

' approximately 12-12, essentially spherically shaped. H

is the base member.

FIGURE 6 is a transverse vertical section thru a modified form of my invention in which the entire device is made of one piece of elastic material, providing thereby structural integration of the main portion 13 and the body member 14. Under some production situations, this construction would be less expensive than joining two separate units. The impact surface 15-15 may be shaped either cylindrically, as in FIGURE 1, or spherically, as inFIGURE 5.

While specific embodiments of my invention have been described, it is obvious that various modifications thereof may be made without departing from my invention. For instance,

While it is stated that the body portion be made of rubber, it is understood that this would include not only both natural and artificial rubbers but also one of the well known plastics and other substitutes having similar elastic properties. And further,

To make the body portion integral with the base, it may be attached to the base by any of well known methods, such as by the use of screws, rivets, nails or adhesive, or any number or shape of prong, such as 4, 4. And further,

The body portion may consist of two or more sections differing in durometer hardness. And further,

To make the body portion integral with the base, both may be made of one continuous piece of suitably elasticmaterial. And further,

The convexity of the impact surface would be provided by a' surface, a cross section of which would comprise, approximately, a portion of a circle or an ellipse, or

'follow a'portion of a multi-polygonal contour that approximates such a convexity, or may conform to any approximation or combination of these. And further,

To provide a convexity as described, the impact surface may be essentially spherically or cylindrically shaped, that is, it may approximate a portion of a sphere, cylinder or ellipsoid or follow a polyfaced contour that approximates such a. convex surface, or may conform to any approx mation or combination of these. And further,

Means, well known to therart, other than that shown in FIGURE 3, may be used to mold the base to the body portion. For example, the prongs 4, 4 in FIGURE'Z may be flared or made with recesses or indentures so as to become integral with the base if the material of the latter ismolded around them. i e

I claim:

1. A tuning fork anvil comprising a body portion of convex configuration, said configuration having a surface a of elastic material, providing thereby an elastic convex impact surface, said body portion integral with a base member wider than said body portion, providing thereby constraint for the operator to direct the fork in such direction as to cause it to strike the surface of said body portion upon an area within a small angle of the vertical, said base member having a fiat lower surface any horizontal dimension of which is large compared with the 7 height of said anvil, providing thereby, while resting on the surface of a table, stability for the anvil and frictional resistance against any tendency to slip on the said table surface.

2 A tuning fork anvil comprising a body portion of convex configuration, said configuration having a surface of elastic material, providing thereby an elastic convex a}: impact surface, said configuration being so shaped as to provide thereby a sector of an essentially cylindrical area for said impact surface, said body portion integral with a base member wider than said body portion, providing thereby constraint for the operator to direct the fork in such direction as to cause it to strike the surface of said body portion upon an area within a small angle of the vertical, said base member having a fiat lower surface any horizontal dimension of which is large compared with the height ofsaid anvil, providing thereby, while resting on the surface of a table, stability for the anvil and frictional resistance against any tendency to slip on the'said table surface. a a

3. A tuning fork anvil comprising a body portion of convex configuration, said configuration having a surface of elastic material, providing thereby an elastic convex impact surface, said configuration being so shaped as to provide therebya sector of an essentially spherical area for said impact surface, said body portion integral with a base member wider than said body portion, providing thereby constraint for the operator to direct the fork in s such direction as to cause it to strike the surface of said body portion upon an area within a small angle of the vertical, said base member having a flat lower surface any horizontal dimension of which is large compared with the height of said anvil, providing thereby, while resting on the surface of a table, stability for the anvil and frictional resistance against any tendency to slip on the said table surface. 1 V

4. A tuning fork anvil consisting of elastic material comprising a body portion of convex configuration, providing thereby an elastic convex impact surface, said body portion structurally integral with a base member wider than said body portion, providing thereby constraint for the operator to direct the fork in such direction as to cause it to strike the surface of said body portion upon an area within a small angle of the vertical, said base member having a flat lower surface any horizontal dimension of which is large compared with'the height of said anvil, providing thereby, while resting on the surface of a table, stability for the anvil and frictional resistance against any tendency to slip on the said table surface.

5. A tuning fork anvil consisting of elastic material comprising a body portion of convex configuration, providing thereby a convex elastic impact surface, said configuration being so shaped as to provide thereby a sector of an essentially cylindrical area for said impact surface, I

face of a table, stability for the anvil and frictional resistance against any tendency to slip on the said table surface.

6. A tuning fork anvil'consisting of elastic material comprising a body portion of convex configuration, providing thereby a convex elastic impact surface, said configuration being so shaped as to provide thereby a sector of an essentially spherical area for said impact surface, said body portion structurally integral with a base member wider than said body portion, providing thereby con-- straint for the operator to direct the fork in such direction as to cause it' to strike the'surface of said body portion upon an area Within a small angle of the vertical, said base member having a fiat lower surface any horizontal dimensioniof which is large compared with the height of said anvil, providing thereby, while resting on the surface of a table, stability forthe anvil and frictional resistance 1 against any tendency to slip on the said table surface.

(References on following page) Sargent 81-15 Roth 84409 X Heiderich et a1. 84422 Gladstone 84422 Gianatano 84422 X LEO SMILOW, Primary Examiner. ARNOLD RUEGG, Examiner. 

1. A TUNING FORK ANVIL COMPRISING A BODY PORTION OF CONVEX CONFIGURATION, SAID CONFIGURATION HAVING A SURFACE OF ELASTIC MATERIAL, PROVIDING THEREBY AN ELASTIC CONVEX IMPACT SURFACE, SAID BODY PORTION INTEGRAL WITH A BASE MEMBER WIDER THAN SAID BODY PORTION, PROVIDING THEREBY CONSTRAINT FOR THE OPERATOR TO DIRECT THE FORK IN SUCH DIRECTION AS TO CAUSE IT TO STRIKE THE SURFACE OF SAID BODY PORTION UPON AN AREA WITHIN A SMALL ANGLE OF THE VERTICAL SAID BASE MEMBER HAVING A FLAT LOWER SURFACE ANY HORI- 